President Barack Obama's 2012 campaign manager will help his former colleague, John Lewis, a Democrat who faces a tough challenge in the at-large House seat race in Montana.

Jim Messina sent a fundraising email to boost Lewis, who worked with him in the office of Sen. Max Baucus, D-Mont.

"And as someone personally invested in the progress and success of Big Sky Country, I know he’s the right person to represent this great state in Congress," Messina wrote on Thursday.

A veteran operative in Montana, Messina served as chief of staff to Baucus before he joined Obama's operation. Baucus will retire after this Congress, creating a domino effect in Big Sky State politics. Rep. Steve Daines, R-Mont., will likely run for Baucus' Senate seat in 2014, leaving a wide-open race for the state's only House seat. Lewis, who filed a statement of candidacy on Aug. 26, has no prominent rivals for the Democratic nomination. But the Republican field is filled with candidates seeking the House seat — as long as Daines run for Senate.

The Democratic Congressional Campaign Committee wants to play for this GOP-held seat. Earlier this month the committee named Lewis to its "Jumpstart" program, which offers early organizational support to certain candidates.

In the email, Messina called the race "one of the most competitive in the country."

Messina's message marks one of the many recent fundraising pleas from campaigns. The quarterly fundraising deadline is Monday.

The race is rated Safe Republican by Rothenberg Political Report/Roll Call.